Free Syrian Army soldiers seize the main square in the northern town of Raqqa, Syria Sept. 2012. / AP

by Ben Hubbard, Associated Press

by Ben Hubbard, Associated Press

BEIRUT (AP) - Syrian government airstrikes killed at least 14 people in the northern province of Raqqa less than a week after rebels seized the area's provincial capital, activists said Sunday.

Also, the U.N.'s top official for refugee affairs said the number of people fleeing Syria could triple this year if the war does not end.

The city of Raqqa, home to a half million people before the uprising against President Bashar Assad began two years ago, could prove a test case for how rebels administer areas they capture.

The rebel groups that led the battle for the city are comprised largely of conservative Muslims, some of them extremists, and videos released over the weekend indicate some fighters have killed captured soldiers.

Recent government airstrikes have shown the limits of rebel control. Even if they hold the ground, they can do little about the government's air force, which often bombards areas recently captured by the rebels, killing fighters and civilians alike.

The regime regularly accuses the rebels - whom it refers to as "terrorists" - of attacking civilians.

Also Sunday, some of the fiercest fighting in a year was reported in Baba Amr, the neighborhood in the central city of Homs that stood for rebel defiance but also for the government's ability to strike back. The Syrian military besieged Baba Amr for a month last year, killing hundreds of people, and eventually retook the area.

On Sunday, rebels and regime troops clashed in Baba Amr, accompanied by army shelling and airstrikes, said the Britain-based Syrian Observatory for Human Rights, an activist group. Amateur video showed clouds of smoke above Homs.

In the Damascus suburb of Harasta, assailants fired a rocket-propelled grenade at a van carrying preschool children Sunday, according to Syrian state TV and a government official. The attack killed one child and wounded nine, three seriously, said the official, who spoke on condition of anonymity in line with briefing regulations.

A video posted online from Raqqa city showed the dead bodies of seven people scattered in a street with destroyed buildings nearby. An off-camera narrator says they were killed in an airstrike.

The Observatory confirmed that strike and said at least seven others were killed in a separate air attack near the province's eastern border.

Over the last year, Syria's rebels have greatly expanded the territory they hold in northern Syria, mostly in the provinces of Idlib and Aleppo next to the Turkish border. In February, they extended their control into Raqqa province, seizing a hydroelectric dam on the Euphrates River. After storming a central prison, they seized most of Raqqa city on March 4, solidifying their control over the next two days.

Raqqa is the first of Syria's provincial capitals to fall completely under rebel control.

Rebel actions since taking the city have raised concerns.

Videos have surfaced in recent days that show dead government soldiers and security officials lying on the ground, their heads bearing gunshot wounds.

One video showed rebels driving the dead body of a military intelligence official around in the back of a pickup truck to show it off. At one point, they lay out his body in a street next to another body. Both have large holes in their heads.

"No one hurt me more than this man!" a voice off-camera yells.

Rights groups have reported extrajudicial killings of regime officials and troops following the capture of other areas, especially of pro-government militiamen known as "shabiha," whom rebels accuse of atrocities. Rebels groups in some areas have set up courts to try prisoners, though it is unclear whether they meet international standards of due process.

Another video from Raqqa posted on Saturday shows three bodies in a street in pools of blood.

"These are the dogs of military intelligence, and they were executed in Clock Square," a voice says, referring to a city landmark.

Other captured regime officials appear to have been kept alive.

Another video posted Saturday showed the provincial governor, Hassan Jalali, along with the chief of President Bashar Assad's ruling Baath party sitting in front of the black flag of Jabhat al-Nusra, an extremist rebel group the U.S. has designated a terror group.

The two were captured by rebels when they stormed the governor's palace on March 4.

In the videos, the second man, Suleiman al-Suleiman, says that before his capture, he was afraid that rebels were extremists.

"But my view has changed, and I have seen that Jabhat al-Nusra has a religious program that follows Allah and his prophet," he said.

There was no way to establish whether he was speaking under duress.

In Aleppo, activists said the dead bodies of at least 20 men were pulled from a river that runs between regime- and rebel-controlled parts of the northern city.

Videos posted online showed the bodies of at least nine men, some with their hands behind their backs and deep head wounds, covered with mud and flies on the riverbank.

Aleppo activist Mohammed al-Khatib said via Skype that locals had identified only a few of the men. He suspected they been taken prisoner by government forces and killed.

In was the second time that large numbers of bodies have been pulled from the river near Aleppo's Bustan al-Qasr neighborhood. In January, activists said at least 65 bodies were pulled from the river, many bound at the wrists.

"They pull bodies out of that river almost every day," al-Khatib said. "Most days it's one or two. Other days it's more."

The Syrian government did not immediately comment on the bodies.

All videos appeared authentic and corresponded with other reporting by The Associated Press.

Syria's crisis began with anti-regime protests in March 2011 and has since spiraled into a civil war pitting government forces against hundreds of rebels groups.

The Syrian government portrays the war as fueled by an international conspiracy carried out by terrorists seeking to weaken the country.

Also Sunday, the U.N. chief for refugees says the number of people fleeing Syria could increase by "two or three times" by the end of the year if the conflict continues.

U.N. High Commissioner for Refugees Antonio Guterres told reporters in the Turkish capital, Ankara, that the international community should work toward ending the conflict.

"If the Syrian conflict will go on and on and on, there is an effective risk of an explosion into the Middle East," he said, adding that it was in "the interest of everybody to stop this conflict before it is too late. "

On March 6, the U.N. said the number of registered Syrian refugees had reached 1 million. Guterres also renewed a call for nations to support Turkey, Lebanon, Jordan and other countries sheltering refugees.

The U.N. says more than 70,000 people have been killed in the violence.